Pharmacokinetic studies of AIDS-related drugs in minority populations are scarce, since most of the studies have been performed in the white population of the United States. It has been suggested that differences may exist between ethnic groups in their waif handling these medications. In fact, reports from a study performed by the Department of Veterans Affairs suggests that black patients may not respond as favorably to treatment with ZDV as compared to the mainland white population (1, 2). However, controversy still exists with regard to these findings (3, 4), because of the more advanced disease state in the minority population. Nevertheless, there is a lack and need of studies addressing these particular issues. Puerto Rico is only second to Washington DC. in terms of AIDS cases per capita in the United States. In addition, Puerto Rico has the second highest seroprevalence of HIV among women. This factor contributes directly to the incidence of pediatric AIDS in our population, since perinatal transmission accounts for the largest percentage (>80%) of HIV infected children. Furthermore, the infection rate in Puerto Rican adults is one of the highest in the nation. Although antiretroviral is playing an important role in the treatment of AIDS in our population; data is lacking concerning the disposition of these antiretroviral drugs in this ethnic group. In addition, patients infected with HIV are simultaneously treated with other therapeutic agents, in order to manage acute episodes of opportunistic infections. Patients are also placed on suppressive therapy to prevent the recurrence of these infections. This represents a source of drug interactions, and some of these are known to alter the PK of antiretroviral agents. The specific aims of the research project are: (1) to determine the Pharmacokinetic (PK) parameters of zidovudine alone and with interferon-alpha in the Puerto Rica pediatric population. (2) to determine the PK parameters of zidovudine alone and combination with other treatment modalities that are used to manage opportunistic infections associated with HIV infection, such as antifungal, antituberculosis and antimicrobial in the adult population. The PK parameters that will be obtained are the bioavailability of the drug, the maximum plasma drug concentration, the time required to achieve the maximum plasma drug concentration, the total body clearance, the volume of distribution, the drug's half-life and the constant of elimination. These parameters will be also determined in the pediatric population. This pharmacokinetic information will shed light into the characteristics of our Hispanic population, providing an unique pool of data to compare with other patient populations in the United States. (3) to provide an opportunity to undergraduate, graduate, and medical students to become active in a biomedical research area that will have an immediate impact in our society. The students will acquire practical knowledge of different analytical methodologies and techniques. Furthermore, they will learn pharmacokinetic modeling and basic statistical analysis. Our long term goal is to understand the pharcokinetics and pharmacodynamics of antiretroviral drugs in the Puerto Rican Population. The implementation of the Clinical Research Center will improve our opportunities towards reaching this goal.